Out of his tree will now complain that I use sources that I cannot really trust, meanwhile he'll believe the tests done a by a racist and known liar.

What about the forensic tests done on bodies at Bergen-Belsen and Dachau? What about the Red Cross reports? What about the total lack of German documents referencing to extermination? What about witness testimonies that contradict the official story (eg. Rassinier or Burg)? For the official Holocaust account to make any sense, you need to ignore loads of evidence or lack common sense.